JP4677625B2 - Optical information reader - Google Patents

Description

  The present invention provides optical information that scans a reading target composed of patterns having different light reflectivities, such as a barcode and a two-dimensional code, reads information from a signal obtained by photoelectrically converting reflected light from the reading target. The present invention relates to a reading device.

As an optical information reading device, a bar code reader for reading bar code indicating the information of product name and price of goods, etc. are widely used in the distribution and retail industries. Such barcode readers are roughly classified into a portable type and a stationary type, and portable barcode readers are required to have a small size, a low driving voltage, and high durability.

  Among portable barcode readers, a barcode reader called a light beam scanning method turns a laser beam emitted by a light source such as a laser diode into a beam and rotates or vibrates a mirror that reflects this light beam. By deflecting the light beam, the bar code is scanned. Then, the reflected light from the barcode is collected, received by a light receiving sensor, and converted into an electrical signal. The obtained electrical signal is A / D converted and encoded, and output as barcode read information.

  As described above, as a mechanism for scanning light by rotating or vibrating a mirror, a configuration in which the mirror is supported by a leaf spring has been proposed (for example, see Patent Document 1). In addition, a configuration in which a shaft is used as a rotating shaft of a mirror has been proposed (see, for example, Patent Document 2). Furthermore, a mechanism called a MEMS type manufactured using a semiconductor manufacturing process including a mirror, a leaf spring, and a drive unit has been proposed (see, for example, Patent Document 3).

JP 2000-315245 A WO03 / 019463 JP-A-10-123449

  However, in the mirror support mechanism using a leaf spring, the center of the mirror rotation operation and the scanning origin of the light beam become far from each other, increasing the requirement for mirror surface accuracy and making it difficult to create. Further, in the support mechanism using the leaf spring, the apparatus becomes large because the rotation axis is far from the scanning origin of the light beam.

  In the mirror support mechanism using the shaft, a shaft and a bearing are required, and noise is generated during scanning due to a collision caused by friction between the shaft and the bearing or a slight difference in dimensions (tolerance). If the requirement for dimensional accuracy is increased, the generation of sound can be suppressed, but the production becomes difficult.

  In the MEMS type, the constituent elements are formed by stacking in a direction perpendicular to the mirror surface, so that the thickness can be reduced in the direction perpendicular to the mirror surface. On the other hand, it is difficult to reduce the size in the direction along the surface of the mirror, and there are many restrictions on arrangement when applied to a barcode reader. In addition, since the resonance frequency is as high as several kHz, high-speed signal processing of the read signal is required, and the cost of the signal processing unit is increased.

  The present invention has been made to solve such a problem, and an object thereof is to provide an optical information reading apparatus that can be reduced in size with a simple configuration.

In order to solve the above-described problems, the present invention includes a mirror driving unit that includes a light emitting unit that emits light and a movable element provided with a mirror that reflects the light emitted from the light emitting unit, and rotationally drives the movable element. And a mover is fixed to one end, and a torsion bar spring that rotatably supports the mover is provided. In the mirror drive unit, two or more torsion bar springs are displaced when the mover rotates. provided in parallel in an arrangement that inhibits the displacement of the non-twisting direction, a mover optical information reading apparatus that will be cantilevered by two or more torsion bar spring.

  In the optical information reading apparatus of the present invention, the light emitted from the light emitting portion and reflected by the mirror is deflected by rotating the mirror, and the patterns having different light reflectivities such as a bar code and a two-dimensional code are used. Is scanned.

  The mover provided with the mirror is fixed to one end of the torsion bar spring and cantilevered. On the other hand, the mover is supported by two or more torsion bar springs, and the two or more torsion bar springs are disposed so as to inhibit displacement in directions other than the torsional direction that is displaced when the mover rotates. Thus, the displacement in a direction other than the direction in which the mirror rotates is suppressed.

  According to the optical information reading apparatus of the present invention, the movable element provided with the mirror is rotatably supported by the torsion bar spring, whereby the center of the mirror rotation operation and the scanning origin of the light beam can be brought close to each other. In addition, since the movable element is fixed to one end of the torsion bar spring to form a cantilever support structure, a support mechanism for setting both ends of the torsion bar spring as fixed ends is unnecessary. Therefore, the apparatus can be reduced in size.

  Further, since the rotating shaft is formed by the displacement of the torsion bar spring in the torsional direction, there is no need for a sliding portion for rotating operation, and there is no problem of sound generation due to friction.

  Furthermore, by adopting a structure in which the mover is cantilevered by a torsion bar spring, it is possible to keep the resonance frequency (natural frequency) when the mirror is rotated and vibrated low, and at a speed suitable for reading. Can be rotationally driven.

  Further, the movable element is supported by two or more torsion bar springs, and the two or more torsion bar springs are arranged so as to inhibit displacement in directions other than the torsional direction that is displaced when the movable element rotates. Thus, the displacement in the direction other than the direction in which the mirror rotates is suppressed, and the reading target can be reliably scanned.

It is a top view which shows the example of whole structure of the optical information reading apparatus of 1st Embodiment. It is a perspective view which shows the example of whole structure of the optical information reader of 1st Embodiment. It is a perspective view of the mirror drive part which shows the example of a principal part structure of the optical information reader of 1st Embodiment. It is a top view of the mirror drive part which shows the principal part structural example of the optical information reader of 1st Embodiment. It is a side view of the mirror drive part which shows the principal part structural example of the optical information reading apparatus of 1st Embodiment. It is a block diagram which shows an example of the plate-shaped torsion bar spring in 1st Embodiment. It is a block diagram which shows the Example of the mirror drive part provided with two plate-shaped torsion bar springs. It is explanatory drawing which shows the stress analysis result of the mirror drive part when a load is added to x direction. It is explanatory drawing which shows the stress analysis result of a mirror drive part when a load is applied to the x direction and the y direction. It is explanatory drawing which shows the tilt angle and z direction displacement of a mirror. It is a top view which shows the example of whole structure of the optical information reader of 2nd Embodiment. It is a perspective view of the mirror drive part which shows the principal part structural example of the optical information reader of 2nd Embodiment. It is a top view which shows the example of whole structure of the optical information reader of 3rd Embodiment. It is a perspective view of the mirror drive part which shows the example of a principal part structure of the optical information reader of 3rd Embodiment. It is a top view of the mirror drive part which shows the modification of the optical information reader of 3rd Embodiment. It is a top view of the mirror drive part which shows the modification of the optical information reader of 3rd Embodiment. It is a block diagram which shows the 1st Example of the mirror drive part provided with three rod-shaped torsion bar springs. It is a block diagram which shows the 2nd Example of the mirror drive part provided with three rod-shaped torsion bar springs. It is a block diagram which shows the 1st Example of the mirror drive part provided with three plate-shaped torsion bar springs. It is a block diagram which shows the 2nd Example of the mirror drive part provided with three plate-shaped torsion bar springs. It is a block diagram which shows the 3rd Example of the mirror drive part provided with three plate-shaped torsion bar springs. It is a front view which shows the modification of a plate-shaped torsion bar spring.

  Embodiments of the optical information reading apparatus of the present invention will be described below with reference to the drawings.

<Example of Configuration of Optical Information Reading Device of First Embodiment>
FIG. 1 is a plan view showing an example of the overall configuration of the optical information reading apparatus according to the first embodiment. FIG. 2 is a perspective view showing an example of the overall configuration of the optical information reading apparatus according to the first embodiment. is there. FIG. 3 is a perspective view of a mirror driving unit showing an exemplary configuration of the main part of the optical information reading apparatus according to the first embodiment, and FIG. 4 is a main part configuration of the optical information reading apparatus according to the first embodiment. FIG. 5 is a side view of the mirror driving unit illustrating a configuration example of a main part of the optical information reading apparatus according to the first embodiment.

  The optical information reading apparatus 1A according to the first embodiment is mounted on, for example, a portable barcode reader 11 including a display unit 11a and an operation unit 11b, and reflects light emitted from the light emitting unit 2. A mirror driving unit 4A for changing the angle of the mirror 3 is provided. The mirror driving unit 4A includes a mover 40A and a stator 41A, and the mover 40A to which the mirror 3 is attached is rotatably supported by two plate-like torsion bar springs 30a and 30b.

  The optical information reading device 1A deflects the light emitted from the light emitting unit 2 and reflected by the mirror 3 by rotating the mirror 3, so that the reflectivity of light such as a barcode B or a two-dimensional code is increased. Scan a reading object composed of different patterns.

  Further, the optical information reading apparatus 1A receives reflected light of the light scanned on the reading object by the light receiving unit 5, and reads information from the photoelectrically converted signal.

  The light emitting unit 2 includes a light source 20 composed of a semiconductor laser (LD) or the like, a lens 21 that collects light emitted from the light source 20 at a predetermined radiation angle, and an aperture that restricts the light collected by the lens 21. Reference numeral 22 is attached to the housing 10 and emits beam light obtained by condensing or collimating the light emitted from the light source 20.

  The light receiving unit 5 receives reflected light reflected by the mirror 3 and reflected light of the light scanned by the reading object, and receives the light reflected by the reflective mirror 50, photoelectrically converts it, and outputs the photo. A diode (PD) 51 is provided.

  The mirror drive unit 4A includes the above-described mirror 3, a frame 42A to which the mirror 3 is attached, and a permanent magnet 43A attached to the frame 42A, and a movable element 40A is configured. Further, the mirror driving unit 4A includes a coil 45A wound around the bobbin 44A, and a stator 41A is configured.

  The mirror 3 is made of glass in this example. The mirror 3 may be made of metal or resin. The frame 42A is made of metal in this example, and a mirror mounting portion 420b that protrudes in a direction perpendicular to the support portion 420a is integrally formed at one end portion of the flat support portion 420a. In addition, the frame 42A is integrally formed with a magnet mounting portion 420c that is perpendicular to the support portion 420a and protrudes in the same direction as the mirror mounting portion 420b at the other end of the support portion 420a. In the mover 40A, the mirror 3 is fixed to the mirror mounting portion 420b on the front side of the frame 42A, and the permanent magnet 43A is fixed to the magnet mounting portion 420c on the back side.

  FIG. 6 is a configuration diagram showing an example of a plate-like torsion bar spring in the first embodiment, FIG. 6A is a front view of the plate-like torsion bar spring, and FIG. 6B is a plate-like torsion bar spring. It is AA sectional drawing of a bar spring. The plate-like torsion bar springs 30a and 30b are made of a metal spring or a resin spring, and one end in the length L direction is fixed to the support portion 420a of the frame 42A as shown in FIG. The other end is fixed to the housing 10. Accordingly, the mover 40A is cantilevered by the housing 10 by the plate-like torsion bar springs 30a and 30b. Both ends of the plate-like torsion bar springs 30a and 30b have a configuration in which the width W is increased in order to increase the fixing strength, and in order to prevent stress concentration, a portion where the width W is expanded is circular.

The plate-like torsion bar springs 30a and 30b are, for example, β-type titanium alloys having a body-centered cubic structure, for example, alloys having a composition expressed as Ti ₃ (Nb, Ta, V) + (Zr, Hf) + O. It is. The plate-like torsion bar springs 30a and 30b and the frame 42A are fixed by bonding. However, in order to increase the bonding strength, the plate-like torsion bar springs 30a and 30b and the frame 42 are preferably made of the same material. The plate-shaped torsion bar springs 30a and 30b may be made of stainless steel such as SUS304, phosphor bronze, high-strength copper alloy KA1025 or the like as long as it is a metal material. Moreover, as long as it is a resin material, you may comprise super elastic plastic etc. with a large tolerance | permissible_range of elastic deformation compared with a general resin material.

  The two plate-like torsion bar springs 30 a and 30 b are arranged in parallel along a direction perpendicular to the reflection surface of the mirror 3. One plate-like torsion bar spring 30a arranged on the mirror 3 side is fixed so that the surface in the width W direction is perpendicular to the reflecting surface of the mirror 3, and the other plate arranged on the permanent magnet 43A side. The torsion bar spring 30 b is fixed so that the surface in the width W direction is parallel to the reflecting surface of the mirror 3. Thereby, the two plate-like torsion bar springs 30a and 30b are arranged at right angles. The arrangement of the two plate-like torsion bar springs 30 a and 30 b described above is merely an example, and the plate-like torsion bar springs 30 a and 30 b may be arranged in directions other than perpendicular or parallel to the reflecting surface of the mirror 3. good. Also, the two plate-like torsion bar springs 30a and 30b may be arranged in a V shape other than a right angle, for example.

  In the structure in which the movable element is cantilevered by a single plate-like torsion bar spring, there are two vibration modes of torsion bar spring torsion and bending, so that the light reflected by the mirror scatters in two dimensions. is there. In addition, even in a configuration in which the mover is cantilevered by two plate-like torsion bar springs, a configuration in which two torsion bar springs are arranged in parallel has two vibration modes of torsion and bending. There is a drawback that the reflected light is blurred in a two-dimensional direction.

  For this reason, in the configuration in which the movable element is supported by the plate-shaped torsion bar spring, two or more torsion bar springs are required, and the two or more torsion bar springs are not in a parallel direction such as a right angle or a Y type. Need to be placed.

  That is, by arranging the two plate-like torsion bar springs 30 a and 30 b at a right angle, the plate-like torsion bar spring 30 a arranged in a direction perpendicular to the mirror 3 is parallel to the surface of the mirror 3. Compared to the direction, it is difficult to bend in the vertical direction, and deformation in the direction perpendicular to the surface of the mirror 3 is restricted. On the other hand, the plate-shaped torsion bar spring 30b arranged in a direction parallel to the mirror 3 is less likely to bend in a direction parallel to the direction perpendicular to the surface of the mirror 3, and On the other hand, deformation in a parallel direction is restricted.

  Therefore, for example, if two plate-like torsion bar springs are arranged at a right angle, the rigidity in the torsional direction, which is the rotational direction, is small, and the rigidity in the other bending direction is large, so that deformation outside the torsional direction can be hindered. it can. As a result, the rotary shaft O is formed between the two plate-like torsion bar springs 30a and the plate-like torsion bar spring 30b, and the coil 40A is energized so that the mover 40A rotates around the rotation axis O. I do.

  FIG. 7 is a block diagram showing an embodiment of a mirror drive unit having two plate-like torsion bar springs. FIG. 7A is a plan view of the mirror drive unit, and FIG. 7B is a mirror drive. FIG. 7C is a plan view of the mirror driving unit, and FIG. 7D is a side view of the mirror driving unit. In the following, an embodiment of the mirror drive unit in which the target value of the resonance frequency is set to around 50 Hz will be described. In the following description, the width direction of the mirror 3 is referred to as the x axis, the direction perpendicular to the surface of the mirror 3 is referred to as the y axis, and the height direction of the mirror 3 is referred to as the z axis.

The plate-like torsion bar springs 30a and 30b have the shape shown in FIG. 6 and have a length L = 2.7 mm. The cross-sectional shapes of the plate-like torsion bar springs 30a and 30b are rectangular, and the width W is 0.2 mm and the thickness T is 0.03 mm. In this embodiment, the material is an alloy having a composition expressed as Ti ₃ (Nb, Ta, V) + (Zr, Hf) + O.

The mirror 3 has a length of 9.3 mm, a height of 2.6 mm, a thickness of 0.55 mm, a specific gravity of 2.55 g / cm ³ , and a mass of 0.034 g. The permanent magnet 43A has a length of 1.0 mm, a height of 2.0 mm, a thickness of 1.8 mm, a specific gravity of 7.5 g / cm ³ , and a mass of 0.077 g. The coil 45A had a length of 3 mm, a height of 2 mm, and a thickness of 0.6 mm. The material of the frame 42A is the same as that of the plate-like torsion bar springs 30a and 30b in consideration of adhesion to the torsion bar springs 30a and 30b. The mass of the mover 40A includes the volume of the mover 40A, the density of the permanent magnet 43A (7.5 g / cm ³ ), and the density of the materials constituting the torsion bar springs 30a and 30b and the frame 42 (5.6 g / cm Calculated from ³ ), it was 0.089 g.

  Under the above conditions, the static thrust at a certain magnetomotive force for stress analysis was found. When magnetomotive force NI = 56.2A, the minimum static thrust in the x direction was Fx = 3.5 mN. The maximum static thrust in the y direction was Fy = 1.47 mN. From the above, the standard of load in the stress analysis was set to Fx = 3.5 mN in the x direction and Fy = 1.47 mN in the y direction.

  8A and 8B are explanatory diagrams showing the stress analysis result of the mirror driving unit when a load is applied in the x direction. FIG. 8A is a side view showing the stress characteristic, and FIG. 8B is the deflection characteristic. FIG. FIG. 8 shows a stress analysis result in the mirror driving unit 4A when a load is applied in the x direction and the direction of gravity G is set to the −z direction. Here, in FIG. 8A, the magnitude of the stress is schematically represented by gradation, and the dark gradation portion is the portion with high stress. Further, in FIG. 8B, the amount of deflection is schematically represented by gradation, and the dark portion of the gradation is the portion with the large amount of deflection.

  In this embodiment, the gravity G is applied in the −z direction, and the center of gravity g of the mover 40A is designed to be on the rotation axis O. As for the load, 3.9 mN was applied in the x direction to the upper 0.1 × 0.1 mm portion of the permanent magnet 43A.

Under the above conditions, the maximum stress was 141.3 N / mm ² and occurred at the fixed ends P1 of the plate-like torsion bar springs 30a and 30b. The proof stress of the material constituting the plate-shaped torsion bar springs 30a and 30b is 900 N / mm ² in this example, and the safety factor is 6.4. Further, the maximum deflection of the mirror 3 was δm = 0.81 mm, and the scanning angle of the mirror 3 was found to be 10.03 °.

  In FIG. 8, only the load in the x direction is considered, but as described above, when the mover 40A is tilted by 10 °, a result that a thrust in the y direction is generated by −1.47 mN is obtained. It is necessary to consider the load. In addition, it is desirable that the barcode can be read even if the optical information reader 1A is in any direction. Therefore, in addition to the load in the x direction, a stress was analyzed by applying a load of -1.47 mN in the y direction and changing the direction of gravity.

  FIG. 9 is an explanatory view showing the stress analysis result of the mirror driving unit when a load is applied in the x direction and the y direction. FIG. 9A is a side view showing the stress characteristics, and FIG. It is a top view which shows a deflection characteristic. FIG. 9 shows a stress analysis result in the mirror drive unit 4A when a load is applied in the x direction and the y direction and the direction of gravity G is set to the −y direction.

  As for the load, 3.1 mN in the x direction and -1.47 mN in the y direction were applied to the upper 0.1 × 0.1 mm portion of the permanent magnet 43A.

The maximum stress was 147.6 N / mm ² and was generated at the fixed ends P1 of the plate-like torsion bar springs 30a and 30b. This value was 4.5% larger than when the load was applied only in the x direction and the direction of gravity G was in the −z direction. The safety factor is 6.1. Further, the maximum deflection of the mirror 3 was δm = 0.8091 mm, and the scanning angle of the mirror 3 was found to be 10.02 °.

Table 1 below shows the stress analysis results of the mirror driving unit 4A using the plate-like torsion bar springs 30a and 30b. FIG. 10 is an explanatory diagram showing the tilt angle and z-direction displacement of the mirror. Here, the equation of motion of the mirror driving unit 4A is expressed by the following equation (1). Further, from the equation (1), the natural frequency is expressed by the following equation (2). Where T: torque (N · m), J: moment of inertia (kg · m ² ), C: damping constant (N · s · m / rad), K: torsion spring constant (N · m / rad) is there.

  Considering the thrust in the y direction, the thrust in the x direction can scan the mirror 3 at about 10 ° in half angle with a small thrust compared to the case where a load is applied only in the x direction.

  Further, considering the thrust in the y direction, when a load is applied, the displacement of the mirror 3 in the z direction and the tilt angle of the mirror 3 tend to increase. However, the tilt angle of the mirror 3 is very small, and even if the distance to the reading target is assumed to be 30 cm, only a displacement of about 0.07 mm occurs at the maximum. Therefore, the displacement and tilt angle of the mirror in the z direction are allowable. Can be in range. Further, it can be seen that even if the direction of gravity is changed, the thrust and the natural frequency necessary for scanning the mirror 3 by ± 10 ° do not change greatly.

  From the above stress analysis results, in the configuration in which the two plate-like torsion bar springs 30a and 30b are arranged at right angles and the mover 40A is cantilevered, the resonance frequency (natural frequency) is set to 50 Hz. I was able to approach. Therefore, it becomes possible to drive at the resonance frequency determined from the spring constants of the plate-like torsion bar springs 30a and 30b and the moment of inertia of the mover 40A, and low power consumption can be realized.

  The dimensions and masses of the plate-like torsion bar springs 30a and 30b and the mover 40A are not limited to those in the first embodiment described above, but the mirror driving unit 4A can be obtained by using the first embodiment as a guide. Can be reduced in size and weight. For example, in the mirror driving unit based on Example 1, the outer dimension could be about 10 × 7 × 3 mm. If the mirror driving unit can be miniaturized, the entire optical information reading device including the light emitting unit and the light receiving unit can be miniaturized, and the barcode reader including the optical information reading device can be miniaturized.

<Example of Configuration of Optical Information Reading Device of Second Embodiment>
FIG. 11 is a plan view showing an example of the overall configuration of the optical information reading apparatus according to the second embodiment, and FIG. 12 is a mirror drive unit showing an example of the main configuration of the optical information reading apparatus according to the second embodiment. FIG.

  The optical information reader 1B according to the second embodiment includes a mirror driving unit 4B that changes the angle of the mirror 3 that reflects the light emitted from the light emitting unit 2. The mirror driving unit 4B includes a mover 40B and a stator 41B, and the mover 40B to which the mirror 3 is attached is rotatably supported by three bar-shaped torsion bar springs 31a, 31b, and 31c.

  The mirror drive unit 4B includes the above-described mirror 3, the frame 42B to which the mirror 3 is attached, and the permanent magnet 43B attached to the frame 42B, and the mover 40B is configured. Further, the mirror driving unit 4B includes a coil 45B wound around the bobbin 44B, and a stator 41B is configured.

  In this example, the frame 42B is made of plastic. In the movable element 40B, the mirror 3 is fixed to the front side of the frame 42B, and the permanent magnet 43B is fixed to the back side.

  The rod-shaped torsion bar springs 31a, 31b, and 31c are formed of a rod-shaped member made of a metal material or a resin material, and one end portion in the length direction is fixed to the frame 42B, and the other end portion is fixed to the housing 10. The Accordingly, the mover 40B is cantilevered by the housing 10 by the bar-like torsion bar springs 31a, 31b, 31c.

If the rod-like torsion bar springs 31a, 31b, 31c are metal materials, as described above, a body-centered cubic structure having a composition expressed as Ti ₃ (Nb, Ta, V) + (Zr, Hf) + O is used. It is preferable to use a β-type titanium alloy, stainless steel such as SUS304, phosphor bronze, high-strength copper alloy KA1025, or the like. Moreover, if it is a resin material, it is good to comprise with a superelastic plastic etc.

  Three bar-like torsion bar springs 31a, 31b, 31c are arranged with one bar-like torsion bar spring 31a on the mirror 3 side and two bar-like torsion bar springs 31b, 31c on the permanent magnet 43B side, In addition, the rod-like torsion bar springs 31b and 31c are arranged in parallel along the direction parallel to the reflection surface of the mirror 3, and the three bar-like torsion bar springs 31a, 31b and 31c are arranged on the vertices of the triangle. The

  In a structure in which the movable element is cantilevered by a single torsion bar spring, there are two vibration modes of torsion bar spring torsion and bending, so that the light reflected by the mirror scatters in a two-dimensional direction. In addition, even if the mover is cantilevered by two or more torsion bar springs, the configuration in which a plurality of torsion bar springs are arranged in a straight line has two vibration modes of torsion and bending, so it is reflected by the mirror. There is a drawback that the emitted light is blurred in a two-dimensional direction.

  For this reason, in the configuration in which the mover is supported by a plurality of torsion bar springs, three or more torsion bar springs are required, and at least three torsion bar springs need to be arranged other than on the same straight line.

  That is, by arranging the three rod-like torsion bar springs 31a, 31b, 31c on the apex of the triangle, it becomes difficult to bend in a direction parallel to and perpendicular to the surface of the mirror 3.

  Therefore, when three rod-like torsion bar springs are arranged on the apex of a triangle, the rigidity in the torsional direction, which is the rotational direction, is small, and the rigidity in the other bending direction is large, and deformation in other directions is hindered. Can do. As a result, the rotary shaft O is formed between the three bar-shaped torsion bar springs 31a, the bar-shaped torsion bar springs 31b, and the bar-shaped torsion bar springs 31c. Rotate around the center. The number of bar-like torsion bar springs is not limited to three, and may be three or more.

<Configuration Example of Optical Information Reading Apparatus of Third Embodiment>
FIG. 13 is a plan view showing an example of the overall configuration of the optical information reading apparatus according to the third embodiment, and FIG. 14 is a mirror drive unit showing an example of the main configuration of the optical information reading apparatus according to the third embodiment. FIG.

  The optical information reading apparatus 1C according to the third embodiment includes a mirror driving unit 4C that changes the angle of the mirror 3 that reflects the light emitted from the light emitting unit 2. The mirror driving unit 4C includes a mover 40C and a stator 41C, and the mover 40C to which the mirror 3 is attached is rotatably supported by three plate-like torsion bar springs 32a, 32b, and 32c. .

  The mirror driving unit 4C includes the above-described mirror 3, a frame 42C to which the mirror 3 is attached, and a permanent magnet 43C attached to the frame 42C, and a mover 40C is configured. The mirror driving unit 4C includes a coil 45C wound around the bobbin 44C, and a stator 41C is configured.

  The frame 42C is made of plastic in this example, and the movable element 40C has the mirror 3 fixed to the front side of the frame 42C and the permanent magnet 43C fixed to the back side.

  The plate-like torsion bar springs 32a, 32b, and 32c are made of metal or resin plate springs, and one end in the length direction is fixed to the frame 42C, and the other end is fixed to the housing 10. The Accordingly, the mover 40C is cantilevered by the housing 10 by the plate-like torsion bar springs 32a, 32b, and 32c.

If the plate-like torsion bar springs 32a, 32b, and 32c are metal materials, as described above, a body-centered cubic structure having a composition expressed as Ti ₃ (Nb, Ta, V) + (Zr, Hf) + O. Β-type titanium alloy, stainless steel such as SUS304, phosphor bronze, high-strength copper alloy KA1025, etc. Moreover, if it is a resin material, it is good to comprise with a superelastic plastic etc.

  The three plate-like torsion bar springs 32a, 32b, 32c are arranged with one plate-like torsion bar spring 32a on the mirror 3 side, and two plate-like torsion bar springs 32b, 32c on the permanent magnet 43C side. The plate-like torsion bar springs 32b, 32c are arranged in parallel along the direction parallel to the reflecting surface of the mirror 3, and the three plate-like torsion bar springs 32a, 32b, 32c are triangular. It is placed on the vertex. Further, the plate-like torsion bar springs 32b and 32c are arranged in parallel to the plate-like torsion bar spring 32a.

  FIGS. 15 and 16 are plan views of a mirror driving unit showing a modification of the optical information reading apparatus according to the third embodiment. As a modification of the mirror drive unit using three plate-like torsion bar springs, as shown in FIG. 15, the three plate-like torsion bar springs 32a, 32b, and 32c may be arranged in a Y shape. Further, as shown in FIG. 16, three plate-like torsion bar springs 32a, 32b, and 32c may be arranged in a triangular shape.

  Regardless of the configuration, the rigidity in the torsional direction, which is the rotational direction, is small, and the rigidity in the other bending direction is large, and deformation outside the torsional direction can be inhibited. As a result, the rotary shaft O is formed between the three plate-like torsion bar springs 32a, the plate-like torsion bar springs 32b, and the plate-like torsion bar springs 32c, and the coil 40C is energized, whereby the mover 40C rotates. A rotation operation is performed about the axis O. The number of plate-like torsion bar springs is not limited to three, and may be three or more.

  FIG. 17 is a configuration diagram showing a first embodiment of a mirror driving unit provided with three bar-like torsion bar springs. FIG. 17A is a plan view of the mirror driving unit, and FIG. The principal part top view of a mirror drive part, FIG.17 (c) is a top view of a mirror drive part, FIG.17 (d) is a side view of a mirror drive part.

  The bar-like torsion bar springs 31a, 31b, 31c have a length L = 2.7 mm, and the cross-sectional shape of the bar-like torsion bar springs 31a, 31b, 31c is a circle having a diameter d = 0.085 mm.

  The bar-like torsion bar spring 31a arranged on the mirror 3 side is arranged at a position of 0.075 mm from the back surface of the mirror 3, and the arrangement of the three bar-like torsion bar springs 31a, 31b, 31c has a length of one side. Each vertex of the 0.4 mm equilateral triangle was designed to be the center of the cross section of the rod-shaped torsion bar spring.

  The movable element 40B supported by the three bar-shaped torsion bar springs 31a, 31b, 31c has a mirror 3 with a length of 9.3 mm, a height of 2.6 mm, a thickness of 0.55 mm, and a mass of 0.034 g. It is. The permanent magnet 43B has a length of 1.8 mm, a height of 2.6 mm, a thickness of 1.8 mm, and a mass of 0.077 g. The frame 42B had a length of 0.5 mm, a width of 2.0 mm, and a thickness of 0.3 mm.

  18A and 18B are configuration diagrams showing a second embodiment of the mirror driving unit provided with three bar-like torsion bar springs. FIG. 18A is a plan view of the mirror driving unit, and FIG. The principal part top view of a mirror drive part, FIG.18 (c) is a top view of a mirror drive part, FIG.18 (d) is a side view of a mirror drive part.

  The bar-like torsion bar springs 31a, 31b, 31c have a length L = 2.7 mm, and the cross-sectional shape of the bar-like torsion bar springs 31a, 31b, 31c is a circle having a diameter d = 0.085 mm.

  The bar-like torsion bar spring 31a arranged on the mirror 3 side is arranged at a position of 0.2065 mm from the back surface of the mirror 3, and the arrangement of the three bar-like torsion bar springs 31a, 31b, 31c has a length of one side. Each vertex of a 0.1 mm equilateral triangle was designed to be the center of the cross section of the rod-shaped torsion bar spring.

  FIG. 19 is a block diagram showing a first embodiment of a mirror drive unit having three plate-like torsion bar springs. FIG. 19A is a plan view of the mirror drive unit, and FIG. FIG. 19C is a plan view of the mirror drive unit, and FIG. 19D is a side view of the mirror drive unit.

  The plate-like torsion bar springs 32a, 32b, and 32c have a length L = 2.7 mm, and the cross-sectional shape of the plate-like torsion bar springs 32a, 32b, and 32c is rectangular, a width of 0.085 mm, and a thickness of 0.035 mm. did.

  The plate-like torsion bar spring 32a arranged on the mirror 3 side is arranged at a position of 0.189 mm from the back surface of the mirror 3, and the arrangement of the three plate-like torsion bar springs 32a, 32b, 32c is one side long. Each vertex of a regular triangle having a length of 0.1 mm is designed to be the center of the cross section of the plate-like torsion bar spring, and the plate-like torsion bar springs 32a, 32b, and 32c are arranged in parallel.

  FIG. 20 is a block diagram showing a second embodiment of the mirror driving unit having three plate-like torsion bar springs, FIG. 20A is a plan view of the mirror driving unit, and FIG. FIG. 20C is a plan view of the mirror drive unit, and FIG. 20D is a side view of the mirror drive unit.

  The plate-like torsion bar springs 32a, 32b, and 32c have a length L = 2.7 mm, and the cross-sectional shape of the plate-like torsion bar springs 32a, 32b, and 32c is rectangular, a width of 0.085 mm, and a thickness of 0.035 mm. did.

  The arrangement of the three plate-like torsion bar springs 32a, 32b, 32c is designed so that each vertex of an equilateral triangle having a side length of 0.1 mm is the center of the cross section of the plate-like torsion bar spring, The plate-like torsion bar springs 32a, 32b, and 32c are arranged in a Y shape.

  FIG. 21 is a block diagram showing a third embodiment of the mirror driving unit having three plate-like torsion bar springs, FIG. 21A is a plan view of the mirror driving unit, and FIG. FIG. 21C is a plan view of the mirror driving unit, and FIG. 21D is a side view of the mirror driving unit.

  The plate-like torsion bar springs 32a, 32b, and 32c have a length L = 2.7 mm, and the cross-sectional shape of the plate-like torsion bar springs 32a, 32b, and 32c is rectangular, a width of 0.085 mm, and a thickness of 0.035 mm. did.

  The plate-like torsion bar spring 32a arranged on the mirror 3 side is arranged at a position of 0.189 mm from the back surface of the mirror 3, and the arrangement of the three plate-like torsion bar springs 32a, 32b, 32c is one side long. Each vertex of a regular triangle having a length of 0.1 mm is designed to be the center of the cross section of the plate-like torsion bar spring, and the plate-like torsion bar springs 32a, 32b, and 32c are arranged in a triangle.

  The dimensions and masses of the rod-like or plate-like torsion bar spring and the mover are not limited to the above-described second embodiment, but the mirror drive units 4B and 4C can be obtained by using the second embodiment as a guide. Can be reduced in size and weight. For example, in the mirror drive unit based on the second embodiment, the outer dimensions can be made comparable to those of the first embodiment described above.

<Modified example of plate torsion bar spring>
FIG. 22 is a front view showing a modification of the plate-like torsion bar spring. The plate-like torsion bar spring 33 may be bent rather than straight. In the plate-like torsion bar spring 33 having a shape as shown in FIG. 24, the rigidity in the rotation (twist) direction is smaller than that of the linear plate spring, so that the thrust required for scanning and the stress generated in the spring are reduced. It becomes possible to reduce.

  The optical information reading apparatus according to the present invention can be used for a barcode reader, a two-dimensional code reader, and the like, and can realize downsizing of the apparatus.

  DESCRIPTION OF SYMBOLS 1A-1C ... Optical information reader, 2 ... Light emission part, 3 ... Mirror, 4A-4C ... Mirror drive part, 5 ... Light-receiving part, 30a, 30b ... Plate shape Torsion bar springs, 31a to 31c ... bar torsion bar springs, 32a to 32c ... plate torsion bar springs, 40A to 40C ... mover

Claims (5)

A light emitting unit for emitting light;
A mirror driving unit having a movable element provided with a mirror that reflects the light emitted from the light emitting unit, and driving the movable element to rotate;
The movable element is fixed to one end, and a torsion bar spring that rotatably supports the movable element,
The mirror driving unit is provided in parallel with an arrangement in which two or more torsion bar springs inhibit displacement in a direction other than the torsional direction that is displaced when the mover rotates, and the two or more movers are provided. optical information reading apparatus, characterized in that the by the torsion bar spring Ru cantilevered. The optical information reader according to claim 1, wherein the mirror driving unit includes two plate-like torsion bar springs arranged in directions other than parallel to each other. In the mirror driving unit, one of two plate-like torsion bar springs is arranged in a direction parallel or perpendicular to the mirror, or in a direction other than parallel and perpendicular, and the other plate-like torsion bar spring has The optical information reader according to claim 2, wherein the optical information reader is arranged at right angles to one of the plate-like torsion bar springs. The optical information reader according to claim 1, wherein the mirror driving unit includes three or more bar-shaped torsion bar springs arranged on a line other than the same straight line. The optical information reader according to claim 1, wherein the mirror driving unit includes three or more plate-like torsion bar springs arranged on the same straight line.